Rotary hammer mill



Sept. 17, 1929. w. J. CLEMENT 1,7 8,39

ROTARY HAMMER MILL Filed March 10, 192 2 Sheets-Sheet '2 Patented Sept. i17, 1929 UNITED STATES PATENT .OFFICE -WALTER J. CLEMENT, or crime, NEW YORK, assrcmon To run :sossnn'r ooarom- TION, or UTICA, NEW YORK, A conronarlon on NEW YORK ROTARY HAMMER MILL Application filed March 10, 1928; Serial No 260,785.

This invention relates to mills of that type wherein a plurality of hammers are carried by a rotary shaftor drum, the hammers-being caused to swing through a material receiving chamber in circular paths by rapid rotation of the drum or shaft. In order that such a.

mill may operate smoothly it is important that the hammers bemounted in both static and dynamic balance. It is also desirable that the hammers shall be so arranged as to tend to prevent the material being operated upon from lodgin in those portions of the chamber inaccessib e to the action of the hammers, this being particularly likely in mills as heretofore constructed at the ends of the chamber beyond the end hammers.

This invention has for its object, therefore,

the arrangement of hammers by which these desiderata may be obtained. The hammers are arranged therefore according to this invention in staggered formation, defining by successive hammers in sequence striking paths converging from the ends of the chamber toward a mid position, the hammers diametrically opposite to each other being positioned at or near the same points longitudinally of the rotational axis. Even though the hammers should be balanced statically it'is found in practice that should those on one side of the axis be offset by substantial amounts longitudinally of the axis from those diametrically opposite, centrifugal force developed in operation set uptremendous bending stresses which unbalance the mill dynamically and cause excessive and even dangerous vibration.

For a more complete understanding of this invention reference may be had to the accomp anying drawings in which Figures 1 and 2 are developments of arrangements of hammers angularly spaced six about the rotational axis.

Figures 3 and 4 are end elevations of hammer assemblies, corresponding to Figure 1, but showing different types of, hammers in the two figures. 7

Figures 5 and 6 show other arrangements for 6 and 8 hammer spacing, respectively.

Figures 7 V and 8 are views similar to Fighammers on the rod 4".

ures 3 and 4 but showing eighthammer angular spacing. y

Referring to Figures 1, 3 and 4 the rotor comprises a plurality of disks 1 arranged in spaced relation lengthwiseof the shaft 2 to which they are fixed for simultaneous rotation by any suitable means, as shown, the

shaft having a flat portion '3 thereon with which a mating portion on each of the disks engages. Arranged in circular series about the shaft 2 and parallel therewith are rods 4. These rods. extendthrough the several disks and serve to carry the hammers. In the form shown in Figure 3 the hammers 5 are fixed in pivotal relation to the rod 4, while in Figure 4 each ofthe hammers 6 is shown as provided with a slot 7 through which the rods 4 pass. When the mill having hammers such as shown in Figure 4 is in operation, these hammers fly out to the limits of engagement between the rods 4 and slots 7 where they are held by centrifugal force. As shown in Figures 1, 3 and 4 six rods 4 are employed, though as will be seen later other even numbers of rods may be employed if desired. p

The hammers may be arranged on the different rods 4 as shown in Figure 1. For example, on rod 4 .a pair of hammers are arranged in the spaces between the end pair of disks 4. The rod 4" has a pair of hammers each of which is positioned in the fourth space inwardly from the end disk 1.- Therod 4 has its twohammers spaced inwardly from the ends ofthe rotor in the fifth spaces. The rod 4 has its hammers arranged in the second spaces, the rod 4 its hammers arranged in the third spaces, and the rod 4 its hammers arranged in the sixth spaces. The rod '4" with its'hammers is diametrically opposite to the rod 4 with its hammers-and it will be noted that the hammers on these two rods are positioned only one space from each other, the hammers on the rod 4 being positioned inwardlyon'e space further than the The hammers on the rod 4", which. is opposite to the rod 4', are positioned inwardly one space further'than the hammers on the rod 4', whilethe hammers on the rod 4 are positioned one space further outwardly than the hammers on the rod 4 and are diametrically opposite thereto. It will thus be seen that while the hammers on diametrically opposite rods are not in exact alinement lengthwise of the rotor they do not depart by more than one space from exact alinement. The hammers on one of these rods are positioned nearer to the ends than on the one diametrically opposite while the rods on either sidethereof have their hammers positioned further inwardly than those opposite thereto. By this means a very close approximation to dynamic balance of the rotor assembly may be produced, attention of course being paid to the balancing of the weights of the hammers for static balance. It is found that where the hammers at diametrically opposite points are positioned at substantially dififerent distances along the length of-the shaft, heavy vibration is sure to result when the rotor is operated 'at the desirable high speeds.

It should also be noted that the hammers on the rods 4 and and 4 are arranged in two series convergingfrom the ends of the rotor toward the center in the direction of rotation of the rotor, that is, the more widely spaced hammers are followed by those progressively less widely spaced. Similarly the hammers on the rods 4?, 4 and 4' converge from the ends toward the center of length of the rotor. It is found in practice that this converging formation and arrangement of the hammers tends to feed the material inwardly from the ends of the mill toward the center, this action being more pronounced where, the convergence is the more gradual, there being a tendency for the material otherwise to lodge at the ends of the mill where it is out of reach of-the hammers. Certain of the hammers are also arranged in series some of which at least diverge in the direction of rotation or converge in the opposite direction to that of the rotation. For example,

the hammers on the rod 4 are more widely spaced than those on the adjacent rod 4 and the hammers on the rod 4* are more widely spaced than those on the adjacent rod 4, but it will be noted that this'divergence in the direction of rotation is much steeper than the convergence of the other series in the same direction of progression comprising the hammers on the rods 4, 4', 4 and 4, 4, 4 and this divergence is in fact too steep to produce any substantial movement of the material bemg ground outwardly from the center of length of the mill. found in practice to result in marked improvement in the operation of the mill.

In F1gure 2 is shown anarrangementusmg six hammer supporting rods 10 as in Figure 1, but with more disks and consequently room for more hammers. In this arrangement 1t will be noted that instead of two hammers on each rod, each rod carries six ham- This arrangement is mers and that these hammers are arranged in is continued in the other group of three rods in the same general line of convergence. For

example, one such line is indicated by the dot and dash line ab, c0l. Each complete series or line passes one and a half times about the rotor in passing from its extreme outward position to its extreme inward position. This may be contrasted with the showing of Figure 1 in which each series is complete in one half of a circumference of the rotor, there being three hammers in each converging series, whereas in the showing of Figure 2 there are nine hammers in each series. With the arrangement shown in Figure 2 the hammers on diametrically opposite rods are located in identically the same spaces so that there is a substantially exact rotation or dynamic balance instead of the closely approximate rotational balance in the form shown in Figure 1. It will be noted'that in each instance the series of hammers lie in lines arranged at an angle to the perpendicular to the'axis of rotation of the rotor.

In Figure 2 it will be noted that the hammers are also arranged in diverging lines in the direction of rotation or converging lines in the opposite direction, but the divergence in the direction of rotation is steeper than.

the convergence in the other series in the same direction. The lines of divergence between the center and ends are complete in 5 hammers-,for example, the inner hammers on the bolt 1O through those on bolts 10a, 6 and c to the outer hammers on the bolts 10- while the lines of convergence require 9 hammers. For example, the successive hammers in each series line are in adjacent spaces to each other in thedirection of presentation in the normal rotation of the mechanism, while in the opposite direction they are spaced two spaces from each other, the slope of the lines being thus much steeper against the normal direction of rotation than in this direction ofrotation. This arrangement also has the advantages of tending to move the material from the ends of the rotor toward its center and when in static balance may also be in exact rotational balance.

In Figure 5 a further modification is shown in which the six hammer carrying rods 20,

20", 20, 20, 20 and 20 each support eight hammers, these being arranged in converging series of twelve hammers each in the direction of rotation and each completing two complete circumferences of the rotating mechanism.

One complete series is shown by the dot dash line m2, my. The hammersof each series are spaced from each other progressively by a single disk being in successive spaces between the disks in the order of their presentation in the normal direction of rotation of the rotor. In the reverse or diverging direction the hammers of adjacent rods are two spaces apart and the series is complete in either 4 or 5 hammers so that here also is a non-symmetrical arrangement of converging and diverging lines of hammers. The rods at diametrically opposite points in this construction have their hammers arranged identically in so far as their spacing lengthwise of their axis of rotation is concerned I and are therefore in dynamic balance.

v In Figures 6, 7 and 8 are shown such mechanisms in which eight instead of six, hammer supporting rods 30 are em loyed. The hammers as shown in Figures and 8 correspond in construction to those illustrated in Figures 8 and 4 respectively. In Figure 6 each of the rods carries a single pair of hammers. The hammers on the 'rod 30 are arranged in the and spaces, while those on the opposite rod 30 are arranged in the second spaces from the ends. The hammers on the rods 3O are arranged on the fourth spaces, while the hammers on the diametrically opposite rod 30lare arranged in the third spaces. Thehammers in the rods 30 are arranged in the fifth spaces, while the hammers 30 are arranged in the simh spaces. The hammers on the rod 30f are arranged in the eighth spaces, and the hammers on the rod 30 are arranged in the multiplicity of series circumferentially of seventh spaces, In this arrangement, as in the arrangement shown 1n Figure 1, the hammers on opposite rods are not in exactly the relation axially but differ therefrom by a single space only and that where-this difference 18 in one direction, as between one set of oppo ite cars, it is in the opposite direction in the case of the diametrically arranged bars next adjacent thereto. v

the arrangement shown in Figure 6 for eight hammer supporting rods each line of the converging series comprises four ham mers, each series being complete in half a circumference of the assembly, in this respect being similar to Figure 1. The divergence in the direction of rotation is only between the hammers on rods 30 and 30. and 30 30 and is complete in 2 hammers. Where more hamconvergence 8D.

'as shown in Figures 1 and 6, it is not possible to havethe hammers-on one rod positioned identically withthose on the diametrically opposite rod, but they need be relatively offset from each otherone space only, and by reversing the direction of such offsetting in the next adjacent rods the relatively small unbalancing effects of such ofiset are largely neutralized. When the number of hammers is an even multiple of the number of spaces, as shown in Figures 2- and 5, the diametrically opppsite hammer arrangement may be identica Having thus described certain embodiments of this invention by way of example, it should be evident to those skilled in the art that various changes and modifications might be made therein Without departing from its spirit or. scope as defined by the appended claims.

I claim:

1. A mechanism of the class described comprising a rotor, and hammers arranged in a.

2. A mechanism of the class described comprising a rotor, and hammers arran ed in a said rotor, the hammers of each series being arranged in circumferential lines inclined to the perpendicular to the axis of rotationof said rotor in one direction and unsymmetrically in opposite directions of inclination,

series in circumferential lines, some convergmg and some diverging 111 the same direction of. rogression, the convergence being at a di erent angle from the divergence, the hammers on diametrically opposite rods being arranged not further than one space from each other axiall of said rotor.

4. A mec anism of the class described having arotor comprisin a shaft and a plurality of disks arrange concentrically on said shaft in spaced relation, rods arranged in circular series in said disks coaxially with said shaft, and hammers carried by said rods in the spaces between adjacent disks, said hammers being arranged in a multiplicity of clrcular series 1n circumferentlal lines, some converging and some diverging in one direction 0 progression, the convergence being at a different angle than the divergence, the

hammers on diametrically opposite rods being arranged not further than one space from each other axially of said rotor, any difierences of spacing of said hammers on diametrically opposite rods being in reversed'direction in circumferentially adjacent diametrically opposite rods.

5. A mechanism of the class described having a rotor comprisinga shaft and a pluralit of disks arranged concentrically on said sha in spaced relation, rods arranged in circular series in said disks coaxially with said shaft, and hammers carried by said rods in the spaces between adjacent disks, said hammers being arranged in a multiplicity of circular series in circumferential lines converging from the ends toward the center of length of said rotor and in lines diverging at steeper angles than the converging llnes, the hammers on diametricall opposite rods being arranged not further thanone space from each other axially of said rotor, any differences of spacing of said hammers on diametrically opposite rods being in reversed direction in circumferentially adjacent diametrically opposite rods. 6. A mechanism of the class described having a rotor comprising a shaft and a plurality of disks arranged concentrically on said shaft in spaced relation, rods arranged in circular series in said disks coaxially' with said shaft, and hammers carried by said rods in the spaces between adjacent disks, said hammers being arranged in a multiplicity of circular series in circumferential lines some converging from the ends toward the center of length of said rotor and some diverging in one direction of progression, the convergence being at a different angle from the divergence.

In testimony whereof I have afiixed my WALTER J. CLEMENT.

v signature. 

